Lock cylinder torque plug



June 13, 1967 J. A. TORNOE Y LOCK CYLINDER TORQUE PLUG Filed July 9, 1965 ile. 4

F G-I INVENTOR. Jan/v 4x5; Tom/a5 United States Patent 3,324,694 LOCK CYLIN ER TORQUE PLUG John Axel Tornoe, Redwood City, Calif., assignor to Schlage Lock Company, a corporation Filed July 9, 1965, Ser. No. 470,707 1 Claim. (Cl. 70375) My invention relates to improvements in lock sets and has to do with the interen-gagement of a key with a rotatable lock cylinder plug useful in locking and unlocking the lock set.

In many pin tumbler lock sets, a key having a bow portion and a shank portion is introduced into a keyway in the cylinder plug and is then rotated. Usually the cylinder plug is connected to actuate portions of the lock structure requiring considerable force or torque for their intended motions. The key shank may be relatively weak. It is customarily made relatively small for easy handling and may be quite thin because of its cross-sectional configuration. Also, the serrations in the shank for actuating the pin tumblers in the lock mechanism may be cut relatively deeply into the shank. These factors may combine to leave very little metal or body to resist the imposed forces. Key breakage somtimes results.

It is therefore an object of the invention to provide a lock cylinder torque plug which can be utilized with standard keys already available and which will assist in distributing the torque stresses so that the key shank is not loaded beyond a reasonable amount.

Another object of the invention is to provide a lock cylinder torque plug effective to transmit additional torque over that otherwise possible without injurying the the key, thus to make available additional force for operating a lock mechanism.

Another object of the invention is to provide a lock cylinder torque plug in which a better engagement than otherwise possible is provided between the key and the cylinder plug.

A still further object of the invention is to provide an improved lock cylinder plug without materially altering the manufacturing process or the general construction of the mechanism.

A still further object of the invention is to improve the interrelationship of a lock cylinder plug and the keys cooperating therewith.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIGURE 1 is a side elevation of a lock set installed in a door panel and indicating the lock cylinder torque plug of the invention in operating position, a portion of a key in engagement with the torque plug being shown in transverse section;

FIGURE 2 is a cross section to an enlarged scale of the structure shown in FIGURE 1 the plane of section being indicated by the line 2-2 of FIGURE 1;

FIGURE 3 is a cross section, the plane of which is indicated by the line 33 of FIGURE 2; and

FIGURE 4 is a cross section, the plane of which is indicated by the line 44 of FIGURE 3.

The lock cylinder torque plug of the invention is normally utilized in connection with a lock set indicated by a knob 6 and of a generally standard character effective to operate a latch bolt 7 installed in a door panel 8. In the usual arrangement, the lock set includes a pin tumbler body 9 having a circular cylindrical bore 11 therein symmetrical about an axis 12. Within the pin tumbler body 9 are disposed appropriate pin tumblers 13 operating in directions normal to the axis 12. The pin tumbler 3,324,694 Patented June 13, 1967 body 9 is usually finished with a transverse planar face 14 and is firmly mounted in the lock set.

Designed to rotate about the axis 12 within the pin tumbler body 9 is a torque plug 17 circular cylindrical in its outside contour and symmetrical about the axis 12. The torque plug makes a turning fit within the bore 11 and rotates relative to the body 9. The plug has a number of transverse passages 18 within which tumblers 19 are disposed for cooperation with the pin tumblers 13.

The plug 17 is likewise formed with a collar 21 disposed at one end thereof and having a diameter sufiicient so that an inner surface 22 of the collar is in abutting relationship with the end face 14 of the cylinder body.

In order to accommodate the customary range of keys, the plug is provided with a keyway 23 formed therein and extending longitudinally or generally in the direction of the axis 12 occupying space on all sides of the axis. The keyway is intersected by the passages 18 for the tumblers 19 so that the tumblers can intrude into the keyway under the customary pressure of springs (not shown). The keyway 23 emerges from the circular cylindrical surface of the plug 17 so as to open onto the interior cylindrical bore 11 of the body 9 and also emerges from the collar 21 through a transverse end face 24 extending across most of the exposed end of the plug. The keyway not only extends entirely through the collar in an axial direction, but likewise emerges from the outer cylindrical surface 26 of the collar in one location to provide what is in effect a slot 27.

Designed to cooperate with the plug and the keyway in the customary fashion is a key 31. This is a body made up of a shank 32 having a cross sectional configuration substantially conforming to that of the keyway 23 and also having a serrated edge 33 designed to cooperate with the tumblers 19. When the serrated edge moves all of the tumblers into a position so that the meeting surfaces between the tumblers 13 and 19 coincide with the surface of the bore 11, then the plug 17 is rotatable within the body 9. When, however the tumblers are in a position as shown in FIGURE 2 with some of the tumblers 13 and 19 not having meeting surfaces in registry with the surface of the bore 11, then the plug cannot be rotated with respect to the body. If the key, as shown in FIGURE 2, is then subjected to excessive twisting force despite the restricting influence of the non-registering tumblers, the key shank 32 will be damaged or broken.

In addition to the shank 32, the key 31 includes a bow portion 34. This has a configuration to include not only an extension 36 on one side of the axis 12 of greater radial extent than the shank 32, but likewise includes an extension 37 on the other side of the axis 12 also of greater radial width than the shank 32. The extension 37 particularly defines a transverse face 38 normal to the axis 12 designed to abut against the end face 24 of the plug or collar so that the degree of penetration of the key shank into the keyway is accurately limited.

Particularly pursuant to the invention, the collar 21 is especially formed. Instead of terminating the collar simply with the planar face 24, in the instance the collar is extended to provide an axially projecting rim 41 projecting toward the key bow 34. Usually, the rim 41 is formed when the plug 17 is being turned and initially is a completely circular rim surrounding the end face 24. The rim 41 in a subsequent manufacturing step is interrupted by the keyway 23 in such a fashion as to leave a pair of shoulders 42 and 43. These are in positions lying on opposite sides of the keyway 23 and in locations in the path of or substantially to abut the extension 36 of the key bow.

There is normally suflicient clearance between the shoulders 42 and 43 and the key bow to admit of ready "ice axial motion of the key into the plug until the face 38 is against the face 24. Then a slight beginning rotation of the key with respect to the plug 17 causes the extension 36 promptly to abut against either the shoulder 42 or the shoulder 43, depending upon the direction of key rotation. When this occurs, then much of the'torque which would otherwise be transmitted from the key shank 32 to the plug 17 along the keyway 23 is transmitted from the extension 36 directly to the respective one of the shoulders 42 and 43. This affords a greatly improved torque transmitting characteristic between the key and the plug and reduces the strain imposed upon the relatively small cross section of the key shank particularly adjacent one of the deeper serrations 33. It is thus possible without substantial alteration in the remaining, standard form of the cylinder plug and without any alterations whatsoever in a standard key 31 to provide an extra interconnection between the key and the plug so that the key and plug are interrelated for transmission of greatly increased amounts of torque.

What is claimed is:

A lock cylinder torque plug for use with a generally planar key of predetermined thickness and having a rel-atively narrow shank extending along an axis and a relatively wider bow joining the shank to define first and second extensions of the bow having aligned transverse faces on opposite sides of said shank and normal to abut at difierent radial distances from said axis, said torque plug comprising a body portion circular cylindrical about said axis, an enlarged collar at one end of said cylindrical body portion and meeting said cylindrical body portion at an inner surface norm-a1 to said axis, said collar being substantially symmetrical about said axis and having a transverse end face normal to said axis and substantially symmetrical therewith, and a rim on said collar and disposed around and extending axially from said transverse end face in a direction away from said body portion, and means defining a keyway through said rim, said head and said body, said keyway being parallel to said axis and in said rim and said collar defining shoulders having opposite surfaces facing each other and parallel to each other and to said axis and being spaced apart only slightly more than said predetermined thickness whereby when said key is fully in said keyway the first of said extensions will be relatively close to said axis in a radial direction and will abut said transverse end surface as an axial stop and the second of said extensions will be relatively far from said axis in a radial direction and will lie in said slot with the trans-verse face of said second extension spaced from the inner surface of said collarand with the opposite sides of said second extension fitting closely between said opposite surfaces of said rim shoulders as rotary stops.

References Cited UNITED STATES PATENTS 213,006 3/1879 Taylor 375 X 1,261,089 4/1918 Yawman 70364 1,789,755 1/1931 Jacobi 70375 3,095,726 7/1963 Schlage 70364 X 3,167,943 2/1965 Schreiber et al 70364 X FOREIGN PATENTS 787,255 7/1935 France.

MARVIN A. CHAMPION, Primary Examiner.

P. TEITELBAUM, Assistant Examiner. 

